PetSafe Microchip Cat Door Installation Adaptor; PetSafe Microchip Cat Door Installation Adaptor is designed to use with PetSafe Microchip Cat Door. It allows the door to be installed into metal or glass doors, windows or walls. Installing into a metal door improves the performance of the microchip reader and provides additional support for window and glass installations. Suitable for glass openings 8.3 to 11.2 inches in diameter. Allows for installation into metal or glass doors, windows or walls. Improves weather resistance for doors installed into glass walls, windows or doors. Significantly improves the performance of the microchip reader when door is installed into metal and metal core doors. Suitable for glass openings 8.3 to 11.2 inches in diameter. Compatible with the Microchip Cat Door (PPA19-16145).